The essential theme is the continuation of earlier work in the field of the regulation of metabolic processes. The specific problems to be studied are: (a) differences between isolated hepatocytes and cultured hepatocytes in respect to the response to hormones; (b) adaptation of uric acid synthesis in the avian liver in response to diet; (c) regulation of glutathione synthesis in rat liver; (d) effects of benzoate on metabolic processes in animal tissues, yeast and fungi; (e) branched-chain amino acid metabolism; (f) metabolic adaptation in the lactating rat, with special reference to the role of prolactin. The main experimental material will be isolated tissue preparations, especially isolated hepatocytes; the determination of metabolites by enzymic methods; assay of enzyme activities; and measurements of rates of metabolic processes. The main experimental animal will be the rat. Experiments on the mechanism of the fungistatic activity of benzoate and related substances will be carried out in the first instance on Saccharomyces cervisiae.